Well after two weeks I fixed the problem; I had a creak/snap in the drivetrain of my fixie. The most intelligent avenue when trying to fix a non-specific problem like this, is to try the most obvious and/or cheapest route. The last time I rode with a partner, two weeks ago he said it looked like a sticky link in the chain. Well the first thing I looked at was the rear hub (Campy Record Track). Indeed it was in need of rebuild so I cleaned it out and packed it with new grease (while I was at it I did the front hub as well). The hubs spun like butter but the noise continued. Then I went to the Bottom Bracket. It too was in need of attention (see "Death of a UN-90). But the noise was still there; if nothing else it was worse. So finally I throw on a new chain and Ta Da!, no more noise. Granted, if I had not re-packed the hub bearings I could have trashed the hubs; and the bottom bracket still would have had to be replaced. So I am amazed at my own incompetence. I fixed the problem backwards and ended up with a better running bike. You gotta love it.